I think the phosphors of CRTs usually had a very low persistence in that the decay time was less than a frame time. If you look at out of sync videos of CRT dis

I think the phosphors of CRTs usually had a very low persistence in that the decay time was less than a frame time. If you look at out of sync videos of CRT displays, it looks as if only perhaps 1/8 of the screen is illuminated at one time.